Sir Rowain was master of Boxbourne Manor, and a vassal of the Earl of Hertfordshire. He was a hero of the Siege of Carlion where he was instrumental in the assault on Lady's Tower. Rowain climbed a siege ladder and defeated three knights of King Vortigern but was mortally wounded by the third, Sir Aethelred Silver Tongue. He died in the winter of 467 of his wounds in a pavilion outside Carlion and is buried in St. Mark's Chapel.